text:
What will be the performance penalties of increasing the wing area of a delta winged aircraft to obtain a lower approach speed?
Delta winged aircraft such as the Dassault Mirage III have an approach speed of 170 knots as specified by the manufacturer.
The Mirage F1 was designed to have a lower take off and landing speed than the Mirage III, what would it have taken to reduce the Mirage III landing speed to 135 knots by increasing wing area and reducing wing loading, and installing the F1 engine, and adding leading edge extensions (without adding canards)?
Could this be done by reducing maximum speed to say Mach 1.4 instead of Mach 2 without sacrificing climb performance?
Some figures:
Mirage III
Thrust: 60.8 kN
Rate of climb: 83 m/s (16,300 ft/min)
Wing Loading:274 kg / sq m
Mirage F1
Thrust: 70.6 kN
Rate of climb: 243 m/s (47,835 ft/min) at high altitude
There is a formula relating change in stall speed to weight of aircraft, not sure if it is applicable here.

It would be more efficient to reduce the static margin, as done on the Mirage 2000.

Peter, do you mean moving the cg rearwards and reducing pitch stability, requiring fly by wire?

Yes. That was done on the 2000, too.

20% decrease in approach speed would be possible? May not be possible to guess accurately without in depth study?

Holding a bunch of stuff constant, to get from 170kt to 135kt approach speed at the same coefficient of lift, you’d have to increase the wing area by about 1.6. That extra wing would be extra form drag. Not sure how much of a contribution on total drag the wing is for the Mirage.

1.6 times the Mirage III wing area is 56 sq metres compared to the Draken's wing area of 49 and the Mirage 2000 of 41.  Drop the Mach 2 requirement and it could be feasible.  Interesting to compare KFIR approach speeds.

What you describe would probably work. In fact rate of climb and operational ceiling would improve. So too would maximum payload. But Mach 1.4 would have been a bad joke.
But your question reads a bit like "How can we improve on the Mirage III wing without doing all the things that were subsequently done to improve on it?"
One approach taken on the contemporary Convair deltas; F-102, F-106 and B-58, was to apply leading-edge camber with a conical profile, apex at the root and widening towards the tip. Developed by NASA, the technique significantly improved low-speed handling and, because it was designed to stay within the root shock cone, had surprisingly little effect at supersonic speeds. The second two designs were both capable of Mach 2. Even the F-102 just about reached your Mach 1.4, despite poor area ruling.

"Could this be done by reducing maximum speed to say, Mach 1.4?"
Yes, but then it becomes valueless as an interceptor.
The delta does not lend itself to lift enhancing devices needed for slow flight, such as slats and flaps, nearly as well as a straight wing.  Increasing camber is perfect for landing as it also increases drag.
Lowering wing loading will lower landing speed, but sacrifices top speed, because of increased drag.  The larger wing will improve climb performance and maximum altitude.
But there are more options, the swing wing, seen on the Mirage G, or a smaller, more
efficient wing.
And another, keep the blazing top speed, and simply build a longer runway.


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Why do gusts change the airspeed during landing, but turning (which changes where the wind is coming from) does not?
As we know it, aircraft are extremely sensitive to gust during its final landing stage. They can lose airspeed if the wind changes to tail, ad thus loose lift or need to adjust their thrust in order o regain the lost speed. On the other side, the opposite happens when encountering a headwind.
On the contrary, we don't take that into account when we consider a fighter jet. When a jet fly's at 20,000 with headwind of 50 knots, turns 90 degrees to the left and has the wind from the right- is it considered to be a change in wind direction or because the whole system is moving along with the plane and the change is more gradual- the aircraft feels no change in actual lift which is derived from the true speed it feels?

It’s a single question, based on a misconception, with three good answers. Voting to reopen.

Don't see any reason do downvote the question.
When you say it didn't include any research I must disagree- as I thoght that "When an aircraft is traveling in an airmass- everything is relative to an airmass".
As I have encountered several casas (And I have more than 5000 horurs accumulated on aircraft- this is not such a trivial question- especially when you encounter this in flight.
As for an example- Yesterday flying at 39000' wind gained 20 knots more from the back- the TAS (and CAS of course) decreased, and the engines were ordered to add thrust until regained speed. Ideas?

Further- you as an engineer should be aware that asking question which seem to be trivial most of the times do hide in them a more serious debate.
Having said the- down-voting a question is irrelevant in a place that should be a place of debate and looking for the truth.

I absolutely agree with Stav and @Koyovis, as this question boils down to basic physics and terminology. It is a very good question, the merrygohappyminusone -guys are triggerhappy again.

Before I get into the question about the turning fighter jet, a few words about airplanes' being extremely sensitive to gusts during final stages of landing. If this was actually true, I'd be dead by now. Seriously. Airplanes are sensitive to gusts during landing, I'll give you that, but I think it's exaggerating beyond reason to say it is extreme.
Now, back to one of the most persistent myths in aviation:
The myth of the downwind turn
The jet in your question does not make a full turn from headwind to downwind, but it does not matter, the physics are the same as in the myth of the downwind turn.
As you stated the plane is moving along with the airmass. So, for the plane, aerodynamically there is no head-, side-, or downwind. Only us on the ground can feel it, as we are locked into to the coordinate system of the earth with our feet.
The airplane is locked into the coordinate system of the airmass, and as long as the airmass itself does not experience acceleration, the airplane flying in it can turn in whichever way, and it will not notice any change in the wind direction.
The direction of the wind is locked into the coordinate system of the earth, so in your example there is no change in wind direction. Not for the jet aerodynamically speaking, and not in the sense of navigation (relative wind changes, but you use the same formulas for the calculations anyway). What does change is the groundspeed of the aircraft, and this is the reason wind (and gusts especially) causes some concerns for landing planes. Takeoff is also affected, but not quite as much as landing.

Can you please elaborate what is the difference between being locked to an airmass and turning inside it, in contrary to having the airmass changing direction?
I mean literature preferably :)
I have been flying for 15 years now and never thought about the possibility that a changing direction inside an airmass can cause changes in airspeed, but somebody made me wonder :)

@ymb1 I'll stitch that in (a bit later), a very good remark.

"..the airplane flying in it can turn in whichever way, and it will not notice any change in the wind direction." Except for changes in Angle of Attack and Angle of Sideslip.

@StavNemirovsky if the airmass changes direction and you do not, you can think of it as a change in the coordinate system. For the airmass to change direction, it has to experience acceleretion into some direction. For the while your aircraft is adjusting to the new cordinate system, by accelerating that is, the aircraft and the airmass are in different coordinate systems. There's some good stuff about coordinate systems and acceleration in Einstein's work ;)

@Koyovis in my answer is based on the premise that wind is not the same as relative airflow. See last paragraph.

The angle of attack is momentary during the turn- not relevant for our discussion.
If an aircraft turns based on its performance charts at a velocity that maintains energy- the angle of attack is not a problem.
Sideslip is the new direction the plane will have to point in order to fly in a desired direction.
Now let's talk about relative airflow then.
Maybe that is the misconception.

@StavNemirovsky If we change the question to be about relative wind/airflow, it would be a totally different question, resulting in totally different answers. I'd keep this one as it is, because it is a good question as it brings up discussion/debate and makes people think. I'd make a whole new question about the relative airflow (preferrably airflow, as the relative wind stuff obviously confuses people). Rephrasing this qeustion would invalidate answers, and as such, I think would be against the principles of this site.

Ok I will have to rephrase it.
Will take some time though :)

It's a change in wind direction but it's not considered windshear. The change in "wind direction" will be imperceptible to the pilot and passengers other than a change in the plane's groundspeed and even that is only detectable with a groundspeed readout.

Next time you fly look at you CAS and Ground speed when the tail wind increases.
There is a reason I asked such an easy question :) I'ts not that easy.

At cruising altitude and airspeed, a change in wind is almost a non-issue. Wind velocity (direction and speed) changing will not noticeably affect airspeed. It will, however, affect groundspeed. Windshear (a sudden and/or drastic change of wind velocity) will affect airspeed momentarily until the plane’s momentum is overcome by the aerodynamic forces acting on it. This will be most apparent as turbulence or loss of performance. It is also most apparent during slow flight due to being so close to your performance envelope edge. The sudden gain then loss of altitude when flying through a microburst is a good example of that.
Flying low and downwind over a mountain is another good example. The sudden downward rush of wind on the leeward side will force your airplane to lose altitude. The plane’s performance remains the same. The cause is that the airplane is flying in an air mass (packet of air) that is itself rushing downward. The plane is just along for the ride. The pilot is forced to drastically increase the plane’s climb performance through the airmass in order to stop their descent before impacting the ground. Like throwing a fish bowl on the ground. If the fish does not jump up, out of the bowl, it will hit the ground with the bowl (never mind that fish can’t fly).
During landing, your slow airspeed and proximity to the ground combined with the vertical component of your momentum makes any loss of performance dangerous. It could lead to a sudden increase in descent rate at the wrong moment or a stall if you are too slow. A change in wind velocity as little as 5-10 knots can have an effect on the plane. That’s why pilots are encouraged to add half of the gust factor (the difference between the steady wind and the peak wind) to their approach and landing speeds.
In your example, it looks like you are concentrating more on changes in relative wind velocity based on changes in aircraft heading instead of windshear. That is different. The aircraft’s airspeed will remain the same. There will be no loss of performance relative to the airmass because the aircraft is flying IN the airmass. The airplane does not care about its performance in relation to the ground unless it is on the ground.
Picture this, you are in an empty B747, in smooth air, full throttle, close to Vne. Someone suddenly releases a homing pigeon at the very back of the airplane. As the little bird races to the front of the big bird, is he supersonic? No. Because he is moving inside the relatively still air of the B747.

Your example at the end is not good because you are talking about an object that does not experience external air.
From your answer above- I am not asking it is dangerous to lose speed or not during cruise, but how does a change in wind direction - whether caused by the airmass changing or by a very quick jet with a turn radius of 30 degrees per second- affect the momentary lift of the aircraft, it tries to maintain the same altitude and engine setting.

And from my experience- together with affecting groundspeed which is obvious- it momentarily affects the TAS and IAS and such, until proper adjustment. just like in a wind shear during landing- in which by all theory and experience- first you encounter the front of the downdraught- which is strong headwind- causing the plane to gain lift and close it's engines a bit in order to maintain the airspeed.

Well, that is my point. The air around the pigeon, on the inside of the B747, is moving at around .9 Mach. Does it feel like .9 Mach to the pigeon. He is inside an airmass, flying his own personal airspeed.

@DeanF. Your pidgeon example is excellent!!! If that does not clarify the dilemma of flying in a moving airmass, I guess nothing will...

Yes, it's understood..
it took me some time to actually understand the reason for that.
the concept of relative speed I clearly understood, but from my logic you could see that my misconception was that by pulling a lot of G's, the aircraft actually proceeds the particles in which it travels, meaning- changing its center of reference.
What helped me understand was something I read in an article, saying that a turn, no matter how quick, maintains equilibrium and all the masses inside a system do travel together unchanging the relations between them.
In contrary to let's say, magic.

Ok, I was wrong. In order to better understand what is happening, other than saying that the plane flies embedded in air mass, it is easier to understand that the turn, no matter how fast it is- maintains equilibrium. meaning- it is not abrupt in no time, but a collection and a gradual turn into the tailwind or vice versa. This is easier understood by looking at each particle of air in which the jet fighter is flying. every second millisecond etc.- that the plane turns, the particles travel with it by the same velocity in relation to the ground, making it move altogether. The situation would be different if the aircraft turn 90 degrees in no time, making the air around it change direction in no time- like happens in a windshear or inversion.

Best to morph your two anwers into one, or delete one of them.

The point that this answer is missing, is that if a plane somehow could instantly change heading by 90 degrees, the resulting pressure on the side of the aircraft would be no different if the plane were flying in the presence of a headwind, tailwind, crosswind, or no wind.

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Would a two-seat light fixed-wing aircraft with a landing speed of 20 knots and a top speed of 180 knots be technically possible?
Watching helicopters come in to land, on occasion, I have noticed that they approach with a forward speed of a few knots, never land straight down. If there is sufficient landing space, would it be possible in some cases to replace the helicopter with a small fixed wing aircraft with low stalling speed?
The Helio Courier is an aircraft which is capable of flying slowly:
With a minimum-control speed of around 28 mph, the Courier is perfectly suited for confined off-airport operations. The first one was certified in July 1954 and powered by the 260 hp Lycoming GO-435-C2B2. - Wikipedia
I want to design (on paper at least), a tricycle retractable aircraft which is capable of the 20-200 knot speed range. Why has no one developed such an aircraft, and can the helicopter be replaced in certain situations by such an aircraft? Will it be technically feasible but commercially infeasible?  (Edit: can I do this with increasing wing area and power only?)
EDIT: What I am looking for is an aircraft that can meet these helipad specifications, see page 25 in the document : https://www.faa.gov/airports/resources/advisory_circulars/index.cfm/go/document.current/documentNumber/150_5390-2  and the image titled "Figure 2–7. VFR Heliport Approach/Departure and Transitional Surfaces: General Aviation". 4000 ft approach and 500 ft obstacles outside that. I can fire up my favorite flight sim and try the approach. Stopping within the helipad could be a problem.

I think perhaps you are not watching those helicopters closely enough.  They may APPROACH with a forward speed of a few kts, but (from my observation, at least) they always reduce that forward speed to zero before they actually contact the ground.  Indeed, many have skids rather than wheels, so a landing with appreciable forward speed would make sparks :-)

Checkout the stall speed of the Antonov AN-2.

Good point about the forwards speed - this means the landing roll is zero for helicopters,  and they can land on a helipad. Any forward speed needs to be stopped. The An-2 has a stall speed of 26 knots but can only go as fast as 100 knots.

Wikipedia puts the An-2 max speed at 139 knots; retractable wheels could be expected to increase that; as a starting point it might be close to your goal.

@jamesqf - I was a passenger on a CH-46 that made a rolling landing at NAS Cubi Point back in 1982 and then taxied to the tie-down location. I didn't get the feeling that it was anything extraordinary.

@Bob Jarvis: Bet that CH-46 had wheels, and was landing on a paved runway.  Both are (from my limited experience, anyway) rather unusual for helicopters.

@stackex555 : the stall speed of 26 knots you indicated might depend on its interpretation. One can argue that the An-2 doesn't even have a stall speed, as it technically doesn't stall: you can just shut down the engine, pull back the stick, and it will come down like a parachute. (you will survive, but the aircraft will probably be damaged).

At least one airframe close to these specs already exists, its a highly modified Wilga by the name "Draco". It can get off the ground in 120 feet and has a stall speed of ~37mph and cruises at ~180mph. With its epic 4000 ft/min climb rate it can get out of tight spaces fast as well. The only thing it lacks compared to your specs is the retractable gear as it was designed as a big gear bush plane.

(source)

The same guy (Mike Patey) also built a pretty wild Turbolance experimental that has some epic short field and climb performance as well and its a retract.
His overall secret sauce is effectively putting a PT-6 on the front end of a small airframe to add a huge amount of power to a light airframe.

Draco is not a homebuilt, it's a (heavilly) modified wilga. Apparently registered in the "experimental exhibition" category.

@PeterGreen thanks for the note! I have updated to reflect.

While "Draco" is indeed impressive, It looks like the actual quote is that a new set of wings reduced its stall speed by 20mph, not to 20mph.  The takeoff and landing speeds seen in videos look rather faster than 20mph, though they involve exceptionally short ground runs.

Specifically: "He designed a completely new airfoil that dropped the stall speed about 20 mph to about 37 mph."  This is in a similar class to WW2-era STOL aircraft.

A retractable would be fine, but some sleek looks would be what I am looking for. Can it land on a helipad?

@stackex555 a sufficiently large helipad maybe.

A stall speed of 37mph is way above the stated goal of 20kt landing speed.

The Turbolance is good, it shows that the small airframe can work with that much power.

@GdD not really that much above. It comes to about 25 knots, give or take :)

Sadly, DRACO is no more https://arstechnica.com/cars/2019/09/the-worlds-best-bush-plane-is-destroyed-on-take-off-in-reno/

@zymhan it sounds like he may be rebuilding it...

At least he's honest enough to admit it was his mistake. Yikes!

Technically possible? Yes. In practice it's so difficult to do that we use helicopters, tilt rotors and VSTOL technology instead.
The byproduct of lift is drag (called induced drag), so if you have a wing with a shape and size that delivers high lift at low speed it will generate a great deal of drag at higher speeds, limiting the effective top speed of the airplane. A wing that is optimized for higher speed produces much less lift at low speed.
If you want the best of both you have to change the wing, which is what flaps and slats do: they increase the lift surface area and change the shape of the wing. If you look a the wing of a commercial jet you see just how complex it is to do that, and understand the limitations. To have an airplane land at 20 knots yet cruise efficiently at 200 you'd need to change the wing shape radically in flight in a way that doesn't interfere with the flight characteristics or present control difficulties. That is a huge engineering challenge, and would likely result in a product that has so much complexity and cost that it isn't better than the alternatives.
You can get close-ish, there are airplanes with a 40kt landing speed and a cruising speed of 160 or so, this is done by strapping a really powerful engine onto a STOL airplane, and powering past the induced drag. 40kt landing speed isn't 20kt landing speed though, that extra 20kt is going to be a toughie.

In essence, you'd need your Helio Courier (or equivalent) to turn into a Bonanza once clear of obstacles, then turn back on final approach.  Tall order indeed...

A very good way to put it @ZeissIkon!

Actually I was thinking of increasing the wing area, keeping the payload constant and increasing the engine power to compensate.  Some sort of delta wing (Delta Dyke) may be more compact and suitable.

@stackex555 Increasing wing area doesn't often pay off.  Absent other changes, you have to quadruple the wing area to cut stall speed in half, and that only if you can keep weight constant.  Since bigger wing is more weight, this race is hard.

Interesting that the Dyke "delta" is actually a very low aspect trapezoid, and the "Flapjack" a very low aspect semielliptical.  May be a better low speed wing.  The Dyke has good top speed, but stalls at 70.  But power would help both.

The planned Vought XF5U "Flying Flapjack" fighter had what you're looking for, but with a top speed of 460mph and a 20mph landing speed. A turboprop version may have taken it to 500mph and nearly zero landing speed.
The prototype V-173 was built and flown and proved the concept sound. It had much smaller engines so its performance was significantly worse, only 140mph top speed with a 40mph landing speed. At one point it came out of an emergency landing on a beach unscathed.
The concept was abandoned because jets appeared. The military was interested in the top speed of the design, which was higher than that of conventional piston planes. They were happy to deal with jets' much higher landing speeds in favor of significantly better top-end performance.

The Dornier Do-29 seems like a really good contender.

It's a tilt-rotor type, which could swivel its engines downwards to improve STOL performance down to a mere 15kt stall speed.  Its maximum speed of 157kt is a little short of what you want, but no doubt this could be improved with modernised engines and a bit of aerodynamic work.
Only two prototypes were built, in the late 1950s.  Flight tests were successful, but the concept was not further developed in that form.  One survives in a museum.

Absolutely.  Tilt those rotors up, make props bigger. (someone may have thought of that).

I think the props are already the maximum size for ground clearance, given that this is both a taildragger and a pusher.  The engines are of course returned to horizontal for cruise flight; other photos imply they're linked to the flaps.

They were probably into increasing lift by "curving" the air flow into a normally turbulent area at high AOA.  The "Flapjack/V-22 Osprey approach is what I had in mind.  Larger props are more efficient. Wanted to try tilt rotors on the Catalina too.

Making the landing gear retractable should bring it to 180 kts already.

The Flying Flapjack needs a high landing gear and high angle of attack. Recent RC scale models have demonstrated the concept. A variable incidence wing would help.  Tilt rotors are an attractive idea, especially lightweight electric tilt rotors.  Another successful tilt rotor that comes to mind is the Canadair CL 84. https://www.youtube.com/watch?v=q6SxyIoSvMM&vl=en  3000 hp needed, though.

Have you looked at Autogyros for your usecase? Or does it have to be "fixed wing" truly?
They tend to have extremely low stall speeds, need very short runways and are capable of reaching speeds near what you ask for with 180 kts.
https://en.wikipedia.org/wiki/Carter_PAV
This thing is still in testing but allegedly was able to do 174 kts in trials.
Another advantage of autogyros is that they're fairly cheap compared to traditional planes.

Autogyros are great, if the rotors could be enclosed within the wings that would be great.

A huge challenge indeed, but then again so are cell phones.  For low speed landings a low aspect ratio with slats and flaps is what you want.  Making them fully retractable is certainly within the range of today's technology.
Next up would be a light and powerful source of thrust.  Here the old PT6A turboprop fits the bill.  The more power the better, and blowing the propwash over the wings and control surfaces is helpful too.  Power would make your plane stand apart from old biplane designs, and make your top speed goal readily attainable, in addition to improving climb performance.
So your project would not be without cost, but you would wind up with a highly versatile aircraft resembling a miniature airliner. (You don't have to sweep the wings as much as they do).  I would pursue it!

Hi lift, yes and as I think of it, what about FBW and relaxed stability? That worked for the Mirage 2000 and reduced its approach speed by 50% if I am correct, to 135 knots.

Deltas are a different kettle of fish for STOL as they can take advantage of vortex lift at high AOA.  But they are inferior to straight wings in lifting capacity.  Experience with the Delta Ray foamie helped launch me into a 2 year study of aircraft design.  Reducing wing loading with deltas only adds to low speed woes in wind.  Slats and flaps on a low aspect straight wing are what you want, retractable for higher speeds, like airliners.

But "relaxing stability" of forward set CG back towards nuetral will help take some load off the tail and downforce off the total lift the plane needs (good for STOL).  But relaxing it to fighter plane level, no, not for this application.

I originally asked the question:

If there is sufficient landing space, would it be possible in some
  cases to replace the helicopter with a small fixed wing aircraft with
  low stalling speed?

Looks like DARPA beat me to it:
https://news.usni.org/2014/03/19/darpa-awards-contracts-search-460-mph-helicopter
Many great answers here:  I can summarize the solutions available as follows:

Add high lift devices to a 200 knot light aircraft, such as leading edge slats, double slotted Fowler flaps, blown flaps, canards and flaps such as the Robertson conversions, in-wing powered rotors or auto-rotating gyrocopter type rotors. (The last one is an idea I have not seen anywhere in print)
VTOL type aircraft such as the Canadair CL-84 fits the bill very well: 15 passengers and 200 knots or more.  A smaller aircraft with less power would work, perhaps with modern electronic autostabilization.
Aircraft with low wing loading or variable incidence delta wings or low aspect ration wings such as the Flapjack. Variable incidence will solve visibility problems.

One option not mentioned are lighter than air hybrids, but I will not go into that right now.
Aircraft can match the high descent rates required for obstacle clearance (500 ft obstacle at 4000 ft from landing area), but land with too high a forward speed to stop within the helipad. It all depends then on the combination of how slow you can land the plane, and the landing roll required.
Taking off in a short space will require high power as well as a low take off speed, but low take off speed does not seem so critical.
The VTOL concept has been proven to be able to meet the requirements. It would be very interesting to see a mini  V-22 or CL-87 and some of the newer electric VTOL proposals I think have this.
Without the 20 knot landing speed, the goal of landing in small spaces in an aircraft has been nicely demonstrated by this video I came across recently. Really amazing:

The 20 knot landing speed appears not be necessary, if the aircraft can land and stop within a short distance: this short distance is a variable and I would attempt several combinations of landing distances that will be useful for the aircraft operator. Basically I am looking for instances where the helicopter can be replaced by a STOL airplane. A piston single with high lift devices and a lot of power would be suitable with antilock brakes or reverse thrust.
Using a flight simulator has been useful for this purpose so far: I hope to do some testing and report. Here is one such trial:

Edit:
There are two ways to approach this: take the fastest two seat kit plans and add flaps and retractable slats, increase wing area or reduce fuel, or make the plane larger.

The Helio Courier is being developed as a turbine powered version: A re- arrangements of parts to make a sleeker aircraft will more or less result in what I am looking for:
http://www.helioaircraft.com/ourplanes_stallion.htm

The Stallion features a 750 shaft horsepower Pratt & Whitney PT6A
  turbo-prop engine. The plane is designed to be fully maneuverable and
  controllable at 37 knots and has a cruise speed of 175 knots.

Edit: It occurred to me that Light Sport Aircraft, with their stall speed limited to 35 knots, might fit the bill if they are fast:
This one with a further STOL kit would do nicely:
Stall Speed with Flaps                      53 km/h / 29 kt
Max Cruise Speed                            305 km/h TAS / 165 kt
Landing Groundroll and Takeoff Roll         150 m / 490 ft
https://www.jmbaircraft.com/aircraft

I didn't see anyone mention the rule of thumb that very few aircraft designs have a stall speed slower than 1/4 the cruise speed. You are asking for a design with a stall speed that is 1/10 the cruising speed. That's asking a lot.
So, let's back up a couple steps. Keep in mind that lift offsets weight in level flight. Angle of Attack and airspeed combine to create lift. Change the airspeed a lot, and you have to change the Angle of Attack a lot to maintain the same lift. Increase the Angle of Attack too much, and the wing stalls. Also keep in mind that when you change the Angle of Attack of the wing, you are also changing the Angle of Attack of the fuselage. One angle will have the least drag, like an arrow pointing into the wind. All other angles are shoving either the roof or the floor into the wind, creating a huge amount of drag.
Leading edge slats and exotic flaps can increase lift (and drag) at lower air speeds, and dropping the control surfaces to below the level of the wing gives you better attitude control at those lower speeds, but all of these things create extra drag at higher speeds, requiring a LOT of horsepower to pull the airframe through the air at those higher speeds, and the frame needs to be strong to take that kind of stress, and that implies more weight which again implies more power, or exotic materials and related construction techniques to keep the strength high but the weight low...
The point here is that such an aircraft would be very complex, very powerful, probably involve exotic materials (to bring the weight down while keeping it strong), and so would be extremely expensive. So, then, the question becomes:
"What is the use case that justifies the expense of such a design?"
Likely, the answer would be, "Some rich guy really wants a cool airplane that will do this." Otherwise, people will come up with far simpler, less expensive aircraft to do whatever it is they want to do with an airplane.
So, if your use case is, "I want to take off and land on a helipad," it would be simpler and cheaper to buy a helicopter and learn to fly it.

Take a look at the Rutan Grizzly. If I remember correctly they called out 25 Kt. minimum fully controllable flight speed. I don't remember the cruise speed, but it was less than 200 knots.
The way I heard it the Helio Courier with its' geared engine etc. became sufficiently expensive to operate that helicopters became a lower cost commercial solution and the Courier went out of production.

The Westland Lysander was a WW2-era aircraft with about your requested top speed and with a reputation for excellent STOL performance, though its stall speed is actually about 60kt.  It was used for inserting and recovering spies in occupied territory, in which the ability to take off in less than 1000ft from some random field or beach was extremely valuable.

Another WW2-era aircraft in this performance range was the Gloster Gladiator, the RAF's last biplane fighter.  It had a stall speed of 46kt with flaps extended, and a maximum speed of 220kt, making it capable of cruising at around 180kt.

One possible way to approach this is to take an example of an actual larger aircraft (4 or 6 seater) that meets the 200 knot requirement and fit a smaller 2 seat cabin and reduce the weight.
If we replace the large cabin with a smaller one and use the same wings, tail and engine and systems we could end up with a lighter, smaller plane that will do 200 knots, and will take off and land slower.
But can this aircraft land at 20 knots? The aircraft in question is this one:
The Spectrum SA-550.
https://en.wikipedia.org/wiki/Spectrum_SA-550

Maximum speed: 250 mph (402 km/h; 217 kn) at 15,000 ft (4575 m),
  Cruise speed: 250 mph (402 km/h; 217 kn),Stall speed: 66 mph (106
  km/h; 57 kn) flaps down, power off

So we have the 217 knot cruise. In order to lower the stall speed, the wing loading has to be reduced, since the stall speed is proportional to the wing loading, we calculate the stall speed at empty weight + 2 passengers and fuel as 500 lbs.
Stall Speed (new) =
Stall Speed at Old Weight x SQRT(New Weight / Old Weight)
This gives 45 knots stall speed.  To get the magic 23 knots we would have to reduce weight to 800 lb, while the weight limit for LSA aircraft is 1320 lb. With retractable leading edge slats and full span flaps, this would bring the stall speed down further.  At the LSA weight limit, the aircraft in question would give 29 knots as a stall speed.
Best look for an LSA that can be fitted with a turboprop, which is lighter, but uses more fuel. A sleek fuselage, mid to high wing and retracts and we are done. In theory.

I can see one reasonable possibility here: fan lift.
You don't want to build a Helio Courier update and try to make it go fast in the air; you want to build something like a Bonanza or Skymaster and make it land really, really slow.
Lift fans in the wings, covered with panels or louvers when not in use, might permit this.  For takeoff, you'd power up the fans and execute a "normal" takeoff, except you only need fifty feet of roll to build up the 20 mph for the wings to add enough to fan lift for takeoff; when landing, you'd power up the fans around the time you go to full flaps, slow down like making a STOL landing, and drop into the extended helipad space. Additional smaller fans in stabilizer and fin could add full three-axis control below what would otherwise be minimum control speed.
Whether this is practical, well, probably not -- but you're not trying to make a full VTOL like a navy F35; you're trying to augment lift enough to use a fifty foot runway in and airplane that can cruise like a fast GA design.

Actually, a helicopter might be better than a fan, as it's  high aspect slower rotor will be much more efficient and top speed will be not bad.  But a fan is possible.

@RobertDiGiovanni I won't argue that a helicopter is more practical.  The OP is asking for alternatives.

The fan would be good if there is lots of power (just like jets, no?), so the F35 does apply.  But for 20-200 mph it is 3rd choice. A large tilt rotor could work too!

Fans can be run off a battery similar to the one in a hybrid or electric car, and recharge from an added alternator on the engine while in cruise or on the ground.  As with hybrids, you get big-engine power for a while, with  small-engine fuel economy.

Excellent idea.  Could have an electric fan for a short, high powered burst of thrust for STOL. I was into putting an electric on the nose of the JU-52 for the same reason.  Definitely a possibility.

authors: Bob Jarvis - Слава Україні

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text:
The Mig 21 and the Mirage III have been criticized for lack of range, is this a limitation of the wing configuration?
Mig 21
Range: 1,470 km (910 mi; 790 nmi) at 10,000 m (32,800 ft) with 2 × K-13A missiles and 800 l (180 imp gal; 210 US gal)
(Wikipeda)
J-7
Combat radius: 850 km (459 nmi, 528 mi) (air superiority, two AAMs and three drop tanks)
JF-17
Combat radius   1 350 km
The J-7 and JF-17 are developments of the Mig 21, why is their range greater?

No. Their range limitation stems from their original concept: relatively cheap simple lightweight agile fighter (MiG-21) or interceptor (Mirage III).
There are plenty of long(er)-range aircraft with delta wing (if that's what you mean). Concorde, for one. B-58. Eurofighter.
For a given class of aircraft, range is primarily a function of fuel quantity and therefore (almost directly) of the maximum takeoff weight. JF-17 is 35% heavier and so has significantly greater range. (It also helps that it and its engine are two generations newer). J-7 is practically the same as MiG-21 and has very similar performance.

Uh range is most certainly a function of wing configuration. - Since range is based on CL/CD, which of itself is a function of the aspect ratio of a wing. - So YES this is (again) a wrong answer.
Other design parameters might've been more important and driving the wing design. But the configuration DOES influence range, to a very very large extend.

Everything depends on everything. But for a given class of aircraft, esp. of the same generation, CL/CD (and most other dimensionless characteristics) will be very similar. For these aircraft in particular, there are many overriding requirements that determine the wing shape, such as speed and manoeuvrability. Moreover, the combat radius for such aircraft is not necessarily determined at the best CL/CD: this would be too slow. The end result is that if you want greater range and/or payload, you'll inevitably need a larger aircraft. (Or a leap to the next generation, or often both).

As I said: other design parameters are considered more important (maneuverability/high maximum wing loading & velocity are prime examples). But range is a direct consequence of the glide ratio. - which is the lift to drag ration (CL/CD). -- Saying "aircraft don't change in CL/CD of the same generation" is a non statement: this is something that is just picked by the designers fairly early on. It can be chosen as one wishes. Picking the glide ratio is done way earlier in the design process than the engines or fuel; as such design range is already chosen at the start.

@paul23: No, this is not a wrong answer, however, your assertion that L/D is a function of the aspect ratio is at least flawed if not outright wrong. Given the requirement for supersonic performance, other non-delta aircraft with natural stability and the same size achieve very similar range performance, so the main proposition of this answer is correct.

@PeterKämpf Again the original question never assumed supersonic to be the case: of course if we make the the driving parameter a delta wing is probably best. - But that's again a choice. It might be a more important parameter (or driving one) than distance or glide performance - however that is still a conscious choice and not something that is an effect. - The point I wish to make is that the reason fightercraft have limited range is based on design choices, supersonic cruise speed is such a choice.

According to your own data you provide, the MiG-21 has the longer range of the 3...
As to the J7 having shorter range, I'd not be surprised if the engine the Chinese use is less efficient than the Soviet one it was copied from (and it is indeed an almost carbon copy of an early model MiG-21), and the same'd be true for many other of the aircraft's systems (my guess would be for example that the MiG would have thinner metal and flush rivets, rather than thicker metal and round headed rivets on the more primitively built J7, making it lighter and more aerodynamically efficient).
The JF-17 is a more modern development of the J7 concept with improved materials, engines, aerodynamics, giving overall better performance.
Mirage III and MiG-21 were both designed for a very similar mission: short range rapid response interception of incoming enemy strikes (and especially bomber strikes) with air to air missiles only (guns being added pretty much as an afterthought, neither aircraft was designed with the agility needed for a dogfighter). They didn't need long range, the idea was to get up to altitude as quickly as possible, launch missiles at the approaching enemies, then get down again to refuel and rearm and do it all over again. Later variants were given increased range and agility to allow them more versatility, but that was the original concept behind both aircraft.

MiG-21 wasn't such a pure interceptor as Mirage III and had guns from the beginning (and no radar). On some modifications in the early 60s the guns were removed, but all later modifications had them again.

Caution: Combat radius is not range. Normally, combat radius = range / 3. This makes the range of the J-7 and JF-17 a lot bigger.

@Peter, certainly, except that the figures in the OP are not compatible: different configurations, different conditions, different versions. For what it's worth, MiG-21 and J-7 are practically the same.


text:
What was the decrease in approach speed of the KFIR over the Mirage 5 due to the canards?
The Mirage III approached at 170 knots according to the Dassault. The Mirage NG and the KFIR C2 as well as the Swiss Mirage 5s added canards to the design, what was the decrease in approach speed due to these changes? I see improvements in low speed handling stated in some references, but does anyone have any references to the approach speeds of the modified aircraft?

The Dassault Aviation website gives the following information: https://www.dassault-aviation.com/en/defense/customer-support/operational-aircraft/mirage-5/  : Landing Speed: 180 mph which works out to 156 knots. The reference given by atacusa seems high.  The Dassault site gives the approach speed for the Mirage 2000 as "140 Kts".

The KFIR has similar airspeed specs as the Mirage 5. However, I'm not clear on what you mean by "Approach Speed".
Approach and Landing Phase:

Vectoring Speed: 220-250 kts
Max Gear Speed: 270kts
Approach Speed: 190-200 kts
Touchdown Speed: 170-180kts

Source


text:
What will be the lift generated by the in-wing free spinning gyros in this design?
Gyrocopters feature a free spinning rotor that generates lift. In this design I have included four free spinning rotors inside the wing of a Cessna 172. Although it will not allow it to take off vertically, it should allow a slow take off and approach.
It all depends on how much lift is generated, how much the system will weigh and if there will be any controllability problems.
This is different from the Ryan XV-5A that had powered rotors in the wings.

what have you tried? why can't you answer yourself? this looks like a project question and you are asking to finish your project for you.

I don't see an actual question here.  I do see a deep misunderstanding of how autogyro rotors produce lift.

Where do you plan on putting the fuel? Not too mention the supports for the rotors, unless you plan on having the bearings in the rings, which has very large losses...

I see a question; the title is a question. That said, I'm not sure it's an answerable question, especially with only the answer given in the question body.

I think the question is clear here: How much will lift change with these rotors in the wing compared to the normal wing?

Bianfable identified the same question that I did. I just had the answer ready for posting but could not due to it being closed.

@Federico Yes everybody should answer their own question and then this site can be deleted.

@Koyovis that's not what I meant and you know it.

I am not an engineer, but I imagine that if opening big holes in the wing would produce extra lift that someone would have done it by now.  Federico, why don't you let someone answer?

An autogiro derives its lifting force from its rotor, which is not powered by an engine but by the airstream flowing in at a positive Angle of Attack: from a relative flow that is directed upward through the rotor disk. So to an extent, the autorotating rotor provides the same function as the wing surface that was cut for mounting the rotors.
How best to compare whether the effect of the rotors is positive or negative? If we look at the L/D ratios of autogiro and fixed wing, we can identify the following:

Autogiro, from Leishman: a maximum L/D of 5 for the complete machine, and of 7 for the rotor only.
Cessna 172, from this link:: maximum L/D of 10.9 for the complete aeroplane, including fixed landing gear.

So fixed wing wins, hands down, by about a factor 2 - and that is for a large autogiro rotor which has much higher L/D than a small rotor. Plus, as @RonBeyer mentions in a comment, not cutting holes in the wing means that there is a convenient place to store fuel in.
Data and graphs from J. Gordon Leishman, Principles of Helicopter Aerodynamics, chapter 12.

None.
What you've come up here is a just holes in the wing, which will allow high pressure air from the lower surface to escape upwards. This will both slow the plane down due to extra drag and reduce its overall lift.
An autogyro's rotor is a wing in itself, deriving spin from forward motion, and then converting spin to lift. You don't get extra lift by putting a wing inside a wing.


text:
If we enter and exit through the emergency exit, then how come when the door is opened for the air bridge the slide does not inflate?
When we enter through the door it's an emergency door. Right? But if we enter through the emergency door then how come when we open it for the air bridge the slide doesn't inflate?

Have you ever heard the command "doors in flight" after boarding was completed? Or "disarm doors"? Follow the link and you know why.

Take a look at the evacuation slide wiki page for full details.
As a part of the preparations for takeoff the flight attendants will arm the doors. This usually means moving a lever on the door.
If the door is armed when it is opened the slide deploys. If it's unarmed it doesn't.

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text:
Thrust is going towards the earth, but the plane is going upwards, Why?
Dears,
I am trying to develop a flight simulation, but I am facing a problem when the plane goes downwards towards the earth.
As shown in the picture below:

In equilibrium state before the plane pitch downwards the following parameters:
Thrust force is 1960 kgf
Weight is 98000 kgf
Lift is 98000 kgf
Drag is 1960 kgf
Angle of attack is 0 deg
The speed was 166 m/s

When the plane pitch downwards towards the earth, The speed increases so lift coefficient increases then the lift force increases till it comes more than the weight and the plane begins to move upwards.
What I am making wrong, what are the lift coefficient or what are the forces that should take the plane downwards?

Isn't lift defined as the force pointing in the opposite direction of the weight? And the aerodynamic force, which is the force actually generated by the wing and is composed of both a lift and drag component so points upwards and backwards from the airframe? That arrow you have labelled as lift doesn't seem to  point in the proper direction for the lift or aerodynamic force. Not an expert so I may be wrong here.

All the forces only affects acceleration, the derivative of the plane's current velocity. When lift increases, it doesn't mean the plane will go up immediately, it will gradually level then start to climb. What you are seeing here is a transient moment when the plane is just starting to level not full leveled, so is still going down.

If there aren't ongoing control inputs, the aircraft will work to return to its prior equilibrium state (assuming positive stability). So if it's only a single, momentary pitch-down input, what you described will play out in oscillations that return you to level flight. If there is ongoing control input to HOLD the nose down to a given (negative) pitch, the control force will increase as speed increases, but then the nose can stay down & speed will build. All depends on what the controls are working to achieve.

And, minor note, drag will increase with increasing speed.

DKNguyen: the lift force is perpendicular to the direction of movement, it is opposite to the weight only when the plane is moving forward.

user3528438: Yes you are right but it doesn't go up immediately it takes a while till the linear velocity changed. But at last it goes upwards.

Ralph: yes the the plane return to the equilibrium state but the lift still increases in the upward direction. Yes the drag force increase but if you composite the drag force here, part of the drag force is composite upward direction which helps in the plane goes upwards. I don't know what I am missing.

@Ahmed Elhamy many folks work with gliders at first.  "thrust" with gliders is force vector in the line of flight, a combination of gravity and the horizontal component of lift.  With a powered aircraft, descending, it is still these forces, plus whatever $thrust$ the engine is adding in the direction of flight.

Congratulations, you have just discovered... Vbg!
First, remember vertical lift opposes weight, and this will be the $cosine$ of your lift vector (which is correctly drawn).  As your speed increases, your plane will depart from its line of flight (which is descending).  With a glider, the wing is now not only supporting weight, it also has a horizontal component which propels the aircraft forward.  With gliders, this little trick only works until form drag eliminates the benefits of using the more efficient wing for thrust at a slightly higher speed.
But, as Peter said, the plane will stabilize at its trim speed, but look at what happens to lift when we "reduce pitch" in the Lift Equation:
Lift = Coefficient of Lift x Density x Area x Velocity$^2$.
Even though reducing pitch makes the Coefficient of Lift smaller, Lift increases by the square of the velocity, so you get more lift by going faster, even though the nose is pointing toward earth.
Now add thrust (from an engine) and, yes, you can climb using excess lift from your wing
(even if the nose points toward earth, or below the line of flight).

what am I missing?

As speed increases, Lift increases, plane begins to rise, now gravity contributes less to forward velocity, plane slows down, Lift decreases, plane descends ...
Now you have discovered ... static stability!

the plane begins to move upwards...

... from its line of flight.

As I can understand from your explanation is that, the plane should elevate upwards slightly but because of thrust force it will take the plane downwards. This means that my thrust force is very small, that's why it couldn't take the plane downwards. Am I right?

Make thrust zero, the plane must descend.  As it angles downwards, it does speed up, but the Lift vector is no longer vertical. Cosine of lift vector (vertical lift) gets smaller and smaller, even though plane speeds up, as angle of descent increases.  At a 90 degree decent (straight down) there is no vertical lift, just drag to oppose gravity.  weight is the force that takes the plane downwards, but thrust will help if there is no vertical lift, but not too many people do that.

Thrust gives forward velocity, which is needed to create lift.

Thank you guys especially Robert and Peter, The problem solved. Yes you were right.

Why is this answer sitting at -3?

@sox with Monica because I dared mention "you can climb using excess lift if the thrust vector is below the line of flight".  Even with static stability, every climb (departure from linear flight in the "up" direction) starts with increase in speed from more throttle.  A staticly stable plane will seek its trim speed, a neutral plane (like many airliners) must add in a bit of pitch up or it will simply speed up.  As it turned out from much study, climbing this way is higher drag, which would limit upward acceleration.  But if I were overloaded, I would dare not raise the nose above the horizon

This phenomena of "levitation without pitchup" can be clearly observed with a simple hand glider by moving the weight back until the tail also requires upforce.  Now there is upward motion from excess lift (created by an increase in airspeed, such as a gust) without change in pitch.  this is valuable, as a gust hitting a glider with excess static stability will pitch up and stall it more easily.  One lesson learned with balsa free flights at the "hill".

Watch the pitch equilibrium better.
Normally, when an airplane picks up speed in a dive, the lift coefficient drops. This will shift the balance of moments (lift and weight times their moment arms) such that the aircraft returns to its old speed (after several oscillations).
Unless you show us the full mathematical model, it is hard to say where you went astray. Calculate the contributions of every part and sum up forces and moments. Then, interpret every residual force and moment as an acceleration (by dividing forces by the mass and moments by their moment of inertia) and integrate them over a small time-step. Repeat. Trim the model with appropriate control deflections and power settings. It is much work, but rather straightforward.

That is what I actually do in my code. But the first section is important, Why the lift coefficient should be dropped. Yes it may dropped for a while due to angle of attack but when the plane nose goes to the linear velocity, the angle of attack will be zero which gives high or efficient angle of attack to increase the lift force.

@AhmedElhamy Why would the plane drop its nose if not from elevator deflection to make it pitch down? This will also trim a lower lift coefficient – there is no good reason why the lift coefficient goes up!

Why this will lower the lift coefficient, the angle of attack should be zero as the plane nose is going with the direction of movement. Is there anything that can affect the lift coefficient other than angle of attack?

Are you sure you're calculating all these forces in the correct axis? Weight is always straight down toward the Earth, but the other three forces rotate with the plane as shown in your diagram.
If the nose of the plane is pointed straight down, then the force of thrust points directly down and thus is added to gravity. Drag will point straight up, and lift will point horizontally.
With so much more downward than upward force, the plane will accelerate very quickly. This will increase lift of the wings (assuming they aren't ripped off) and negative lift on the horizontal stabilizer. So, assuming no further elevator input, the plane will naturally rotate upward and pull itself out of the dive. This is a passive safety feature inherent to the design of most (but not all, particularly military) airplanes.

"The plane will naturally rotate upward and pull itself out of the dive", not if the tail stalls from the wing pulling the plane "sideways", friend.  This is the extreme case of a "staticly stable" configuration.  The wing over powers the tail, the plane will not "pull out". It is actually easier to pull an "unstable" plane out of a dive (it "turns" easier).  In a practical sense, chopping power is a very good move to control speed in a dive to avoid Vne, as you suggest.


text:
Power changes and trim forces. related to position of Center of Mass (CoG), or Center of Pressure?
Theoretically (and Actually) do power increases cause a pitching tendency (and a need to adjust pitch trim), because the thrust line is not aligned with the Center of pressure, or, as I understand it, because the thrust line is not aligned with the center of mass (CG)?
I was recently told that the Cessna 182 is particularly sensitive to abrupt power changes in the landing phase (at slow airspeed) because it is a high wing aircraft, and the thrust line is below the Center of Pressure. i.e., Increases in Power generate a pitch up moment, requiring down trim to compensate, and reductions in power generate a pitch down moment, requiring nose up trim to compensate.
This strikes me as wrong, I believe it the alignment of the thrust vector with the center of mass of the aircraft, (the Center of Gravity (CG) as it is called), that determines the moment generated by thrust vector.

I believe the propeller on the 182 affects the elevator more.  As you pull back power, the propeller slows the airflow hitting the tail.  The effect of the tail is greatly reduced and the nose will drop.

@Wbeard52, yes this makes sense as well. This effect could also be part of the cause of the pitch moment.

Your intuition is correct.  Each of the three principle axes of the aircraft originate at the center of gravity.  Therefore, all rotation in either pitch, roll, or yaw occur around the CG.
The center of pressure is a place along the chord where the lifting force acts on the wing.  It is not a pivot point like the CG is.  In fact, an increase or decrease of lift will actually produce a pitching moment around the CG if they are not co-located along the longitudinal axis.  This contributes to the relative stability (or instability) of an aircraft.

Well I have an issue with this definition as I've seen this happen in low wing and high wing airplanes. I don't know if the effect is more pronounced in a Cessna than a Piper as I've never personally flown a Cessna but I know it happens on a Piper.
I've heard a different story about it. When you trim your aircraft you set a combination of power and pitch and that gives you a particular airspeed that allow for level flight.
When you abruptly increase power your velocity can not increase as fast due to mass inertia and newton's second law. On the other hand pitch is quite free to change and it will adapt to the new power setting in order for the aircraft to stay at "equilibrium" regarding the power, pitch, speed relation.
We know that power is used to compensate drag and drag is a function of speed and AOA. Therefore taking out all other parameters we can get the following relation.
$Power = AOA * speed^2$
With a quick increase of power and the speed remaining constant you need a quick increase of your AOA that will put the nose up and therefore increase pitch.

Who "told" you this?  When in doubt, start with gliding.  Does the high wing have any "abrupt pitch tendencies".  This Cessna is about as rock solid as you can get as a safe design aerodynamicly.
Using the CG as the center of aerodynamic torque, in stable flight, all pitching moments = 0.
Looking at the front of the plane, at any given speed, the position of the center of drag in relation to the CG will contribute to trim.  This means that less tail down force is required to "zero" any pitching force from the wing center of upward lift being behind the CG.
So we can isolate the issue to when power is applied and conclude the prop blast (or lack of it) will affect pitch by increasing airflow over the elevator.  But downthrust angle is designed to compensate of this effect.
So if a 182 is experiencing "abrupt pitch changes" one may wish to have the mechanic check the engine mounts.  Another possible cause could be the CG is too far forward, which should be checked preflight.
Actual flying experience in the 182 at altitude will be a great way to sort out any alledged vices.  It has slightly more power than a 172 (160/180 hp vs 230 hp)

I apologize if I am mis-readng you, but if you are denying that there is a pitching moment from power changes, well, that is not even in issue. I have 300 hours in the 182, and I noticed this immediately on the first 182 sortie I flew after transitioning from the 172. On final to land, pulling power causes an immediate pitch down (before airspeed decreases), requiring nose up trim to compensate, and increasing power causes a pitch up that requires nose down trim. I do think prop wash over the elevator may be the explanation for this, but why is it not as bad in the 172?

You may have misread my post, specifically my use of the word "abrupt". I did not say there were "abrupt" pitch tendencies, I said there were pitching moments when making "Abrupt" Power changes. This is a common effect. In the F-4 Phantom, for example, the engines were canted downwards at the back specifically to ensure that the thrust line passed close to the CG (vertically) to avoid this, because it is a significant issue.

@Charles Bretana it pitches down when power is taken out for the exact same reason it pitches up when power is added: (more powerful prop wash effects). Granted, with more power and speed, you move everything to the middle (right on up to the X-15).  Downthrust is the cure for high wings (look at a Catalina).  It's important to know the relative impacts of design (and to have a good mechanic).

@Charles Bretana the pitch down when power out may be in there as a safety feature because the 182 is heavier, but, as you have noted, it means that full power on pitch up tendency has to be carefully watched.  Even in a 172, a little "push" on the yoke helps to hold Vy (and certainly a lot more going into cruise).   That is from the high wing (relative to CG).

In cruise, depending on the aircraft the elevator is actually creating negative lift to have equilibrium. But when you increase power you still have a nose up attitude change. Following your theory we should have the opposite happening

@MaximEck you may be confusing thrust and drag torque.  The high wing drag eliminates the need of tail downforce (or contributes to it).  With this particular design, prop blast hits the elevator, increasing pitch up tendency.  But adding downthrust is helpful in general because adding power increases speed which pitches up....  Before we got to 150+ mph, the high wing and a properly sized horizontal stabilizer was a clever way to pitch the wing to its optimal AOA without the need for tail downforce.

My point is only that this pitching up moment happen in any aircraft, even in citation jet where the elevator is away from the jrt blast, the thrust is above CG and the wings are below CG. Therefore prop last cannot be taken as the main reason to explain the pitching up tendency. But it is totally possible to increase it for the cessna 182 particularly at slow speed when you are already pulling on the yoke to maintain the nose up.

@MaximEck that is true.  And interesting that these new big jet fans will have huge amounts of "pull", even without affecting airflow at the tail as well.  The 182 does have a bit more power, which increases effect 2 ways.


text:
How effective was the computer-controlled gunnery on the B29?
The Boeing B29 Superfortress was equipped with multiple gun turrets which were linked to a central
computerised fire control system. This training film covers the gunner's control interface, which looks astonishingly advanced for the 1940's.
How effective was this gunnery arrangement?
Are there published statistics showing how its defences compared to other bombers of the time?
Related question.

That's more a question about gunnery than aircraft, especially when asking for statistics on gun effectivity.

The system was really the original true "fly by wire" control system, just not a flight control.  The gunner's sight head used Selsyn synchros to send voltages to the computer representing azimuth, elevation and range, and the computer sent modified voltages to Selsyns in the turret(s), and where the guns were pointed was not where the sight head pointed, but where the computer decided they should be pointed after applying all the correction schedules. So the gun barrels were never actually parallel to the sight head axis, but pointing somewhere else as the computer saw fit.


text:
If the intake of a running jet engine is blocked for some short duration what would be the sequence of events following it?
If the intake of a running jet engine is blocked for some short duration what would be the sequence of events following it? Will it cause any damage to the engine parts?

Blocked by what? This seems to be a purely hypothetical question, which isn't really what the site is about.

@DavidRicherby: Could happen, but mostly on the ground.

This site is loaded with hypothetical questions, why pick on this one?

This explanation is for a subsonic aircraft, a similar process occurs at higher speeds.
Causes
A bird, an object or ice can disturb the flow of air entering the engine. Another source of compressor stall is an excessive engine angle relative to the air flow, when a large pitch or crab is forced, or when entering the wake of a preceding aircraft.
Immediate effect
Regardless of the case, if the flow departs from the operating area at some location in the engine compressor, an aerodynamic stall of the compressor can be experienced exactly like a wing can stall:

Stalled airfoil in a wind tunnel, flow separation and turbulence visible. Source
The air boundary layer detaches from compressor blades surface and becomes unsteady.
Compressor stages are made of rotating blades and stationary vanes delimiting small channels:

Source
The problem develops from a low mass flow region, with disparities increasing until the flow stops, in a process called rotating stall:

A passage is blocked by slow air (detached boundary layer in orange), upstream air tries to use the next passage:

However the next passage is reached under a higher angle of attack, this condition tends to stall this passage too.

This effect propagates rapidly from one blade to the next on the compressor stage.

As passages are blocked by detached air over stalled airfoils, pressure increases in the passages and upstream:

Detached airflow is very turbulent with changing velocity (including negative values).

Stalled cells keep rotating at a fraction of the compressor rotational speed, pressure around the blades varies periodically.

Blade/vane vibrations can start. Vibrations are not good for an engine, buffeting can break a metal part if resonance occurs.
A turbine engine works by reaching a precise equilibrium around the flow of air in the compressor, the combustion chambers and the turbine:

The turbine must receive a given quantity of energy to drive the compressor at the proper speed.

Combustors must receive the exact quantity of fuel and air to deliver the energy to the turbine.

Compressor must provide the required quantity of air to the combustors.

(Let's ignore the fact that turbine engines have most of the time two or three spools, i.e. compressor-turbine assembly with a mechanical linkage, each one turning at its own speed, which have to find this shared equilibrium).
As soon as air velocity or pressure changes for any cause, a new equilibrium must be found, else bad things start to happen. In a compressor stall, sometimes no new equilibrium can be reached. This lead to dramatic consequences.
Subsequent effects
After the rotating stall, a cascade of events is triggered:

Pressure decrease at combustion chamber inlets
The compressor being now less efficient, pressure downstream the compressor decreases in addition of being unstable. The magnitude of the pressure variation is somehow limited by the plenum chamber effect of the compressor diffuser for an axial compressor (by the diffuser stator after the impeller for a centrifugal compressor).

Location of the diffuser, source

Depending on whether a new balance can be found or not, combustion may continue while the rotating stall occurs. In that case it'll be at reduced power due to the less efficient compressor, and a lower fuel flow is required.

It may be necessary to shutdown the engine and restart it to get out of the compressor stall.

Overheating
Less air being now available for combustion, if fuel flow is not reduced, the mixture becomes too rich, combustion temperature increases, overheating occurs in the combustion chambers and downstream in the turbine. As the materials used for the combustion chambers and the turbine are working at their highest sustainable temperature, any unwanted increase can damage them.

This can happen if the fuel control unit (FCU) doesn't limit fuel flow correctly and attempts to maintain previous thrust / fuel flow.

Surge
The compressor diffuser (or plenum in a centrifugal compressor) is upstream of the combustion chambers. The latter is a very high pressure region at hot temperature. If the diffuser pressure is too low compared to turbine inlet pressure, hot gas can start flowing back into the diffuser and the compressor. This is a surge.

The surge creates a loud bang and the pressure wave can damage the fan and the engine inlet.

The surge can be associated with flames getting out of the engine via the exhaust pipe or engine inlet. Flames are due to the ejection of unburnt fuel accumulated in the combustion chambers.

Compressor elements are not designed to sustain hot gas from the combustion chambers they may be damaged if expulsion is repeated.

Again, the engine may recover itself from the surge if there is no damage. The cycle can repeat but at some point damages are inevitable.

More on compressor stall: What exactly is a compressor stall?

Loss of control
The surge also creates an asymmetrical additional thrust leading to a yaw force, for an engine not on the center-line.

If the surge is important and the aircraft in a critical phase (e.g. rotating to take off), the yaw effect can lead to a loss of control.

Stall actual cases

In this accident due to icing, the repeated surges are suspected to be the result of the improper fuel flow management. Both engines were destroyed.

This accident was caused by a compressor stall at large crab angle.

In this takeoff accident, the yaw effect of the surge was actually interpreted as a collision with another aircraft.

Fortunately most compressor stalls are handled safely, like this one near takeoff rotation speed (note the flames at 0:34).
Obviously a compressor stall is a serious problem, so engine designers spend a lot of efforts to prevent it and maintain the engine working point in a safe (and efficient) state. For instance using vanes with variable angle of attack and air escape paths, etc.

The compressor would stall. This will cause a sudden rise in turbine temperature, which could damage the turbine(s). In the end, with no air intake, the flame will die out and the engine would stop.

This.  Simple questions deserve simple answers.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Why does the V-22 Osprey have twin stabilizers?
I've noticed that the Bell Boeing V-22 Osprey has a twin vertical stabilizer, while the AugustaWestland AW609 has a T-Tail.

Bell Boeing V-22 Osprey with twin stabilizers. Credit: Boeing

AW 609 (T-Tail) Credit: Airliners.net
I understand why it was used for fast jet fighters, but why was it used for the V-22? What are the advantages?

The V-22 was designed to be operated by the US Marine Corps on-board US aircraft carriers. Any airplane that operates off of a carrier has to be relatively compact in order to be able to fit onto the carrier's elevators and short enough to fit into the hangar deck. A twin tail spreads the elevator authority over 2 smaller control surfaces instead of 1 big surface, making the aircraft shorter, and the placement at the ends of the elevator reduces its overall size footprint.
The other benefits of a twin tail are a reduced radar cross section (the V-22 needs all the help it can get there) and increased redundancy as if one tail is damaged there is another one available. The wide placement of the stabilizers reduces the chance that enemy fire will take out both at once.

Thanks for the answer, but is there a difference in terms of aerodynamics (other than being able to use one tail if the other is damaged)?

I'm not sure I understand your question @SharkyPanda.

@SharkyPanda: Look here for an answer.


text:
What is the correct answer to this Mass and Balance calculation?
I was practising some mass and balance questions and I found that my answer is a little bit too far from the listed answers. Can anyone help me to see if I did something wrong?
The question was:

Given that the Dry Operating Mass (DOM) is 27 372 kg, there are 12 000 kg of
  trip fuel and 4 000 kg of fuel are expected on landing, what is the
  maximum allowable traffic load for the Medium-Range Jet Transport
  (MRJT) aeroplane?

23,923
23,528
19,005
19,428

My solution was:

Operating mass = DOM + Usable fuel
$27 372 - (12 000 - 4 000) = 19 372 kg$

That doesn't match any of the options, so what is the correct answer?

See this document, in particular the graphic on the last page. It seems you miss a parameter: ZFM or TOM.

What is the MSTOM?

It strikes me that your formula is correct, you just didn't follow it -- Operating Mass = DOM + usable fuel = 27 372 + (12 000 - 4 000) = 35 372

Your answer is not included in the set of options.


text:
How to get an accurate time of arrival to the en-route alternate airport during flight planning?
I was thinking about accurate criteria of selecting en-route alternate (ERA) weather from ground (planning stage) especially for ERA 3% contingency flight plan.
As we all know we should care about one hour before to one hour after of arrival time into destination hence the main question here how we should know what is the estimate time of arrival into destination i.e. 1400Z.
Personally what I am doing as a airline pilot is crosschecking the nearest waypoint to that "ERA" thence I can tell inaccurate estimate.
Is there any idea how we can get accurate estimate of en-route destination during planning stage (on ground) that can give us exact ETA of destination?

This is very much like the information mandated for EDTO/ETOPS.
Computerised flight planning systems should have the ability to calculate the ETP, equal time  point (aka CP) based upon ERA/ERAs selected. If 2 ERA are required due to the length of flight, depending on the geographical disposition of the ERA you'd get an ETP for each pair, ie ETP1 for DEP Stn/ERA1, then ETP2 for ERA1/ERA2, then ETP3 for ERA2/DEST Stn.
The earliest ETA for ERA1 would be a diversion from ETP1 and the latest would be from ETP2 and you would need to subtract/add the 1 hr buffer.
And so on . . .


text:
Would a takeoff be aborted if 'rotate' is not called out?
As captain of a Boeing 747 on a take-off roll I am expecting my co-pilot to call out V1, Rotate, but he does not call out rotate. Do I abort the take-off?

Do you mean you don't reach Vr or the callout is just not made?

You're the captain. Surely you have briefed your crew on what to do in case of abnormal situations during the takeoff run?

I can't believe that a captain would ask a question like that. That's too much speed for an abort.

@mike - The way I read that, it was a theoretical question, but now that you mention it...

That could end up being a really bad idea if you've accelerated past your V1 speed -- your abort would then put you off the end of the runway, and the consequences from that range from bad to catastrophic.
A much better idea would be to look at the markers on your airspeed indicator, and if you're at/above rotation speed, go ahead and rotate.  Then sort out what's up with your copilot.
The worst case is, he's incapacitated, unconscious, experiencing a stroke or heart attack or something similar, and you'll probably end up returning to land as quickly as possible.  While the idea of staying on the ground to get him EMS help sooner might seem to be appealing, he'll probably NOT get better attention if your aircraft just ran off the runway, through the airport fence, and into whatever terrain/water/civilization lies beyond, because you didn't start your abort until several seconds after you should have been flying.  Better to come back and land with ONE sick person on the airplane, rather than crash, making your copilot now one of potentially MANY injured/scared/incapacitated people on a damaged jet -- and he with the very least ability of any of them to evacuate himself!
Or, maybe he got distracted and he's fine, and after he overcomes his embarrassment for missing the important callouts, the rest of the flight will go fine.
So, no, if the copilot doesn't call "V1, Rotate" I would NOT recommend aborting the takeoff.  If you see him slumped over when he should be making an "80 knots" or "airspeed alive" call, that might be a different decision; at that sort of speed you're in no danger of running off the runway & you could probably taxi back to the gate promptly.  But if he's missed his calls at significantly higher speeds, aborting is a bad plan.

I really enjoyed reading that answer!

As a former 747 captain, I agree completely with your answer. Aborting above V1 should never be done. Doing so will typically result in an accident. You might be able to get away with aborting a few knots over V1, but take a look at https://avherald.com/h?article=40738955/0036 for what happened when they aborted 12 knots above V1. The callouts should be considered more as reminders than commands. The flying pilot is responsible for rotating at the proper speed.

About the only time you'd abort a takeoff after rotation speed is if you're taking off from Edwards AFB's runway 15/33 or some other absurdly long runway, where you don't have a V1.

What is an "airspeed alive" call? (should I ask a new question?)

@FreeMan "Airspeed Alive" is called at the first indication of airspeed.  Typically, airspeed indicators on a jet don't indicate anything below a particular threshold value (40-60 KIAS), so once you pass that speed they become active / the indicator starts moving (is "alive").

Very well stated answer and valid common sense reasons not to abort above V1 and on a missed V speed call.
80 kts and 100 kts also serve as incapacitation calls and 100kts  caution yu are entering a high energy state in case pf any abort and something to be extra mindful in case of wet/slippery runways.
Here is a good case why not to abort at V1 and above gor a heavy jet
https://aviation-safety.net/database/record.php?id=19720418-1
https://aviation-safety.net/database/record.php?id=19960613-0
There is a case, exceptionally. When a take off must be aborted after V1 ...when you have no other choice but to.One case might be encounterng flight control failure such as horizontal stabilizer.Another case might be dual/all engines failure case
 You are not going anywhere with these two scenarios and better salvage a crash close to the runway,stopway and clearway then at height.
Another case where it might be tempting to abort a feq seconds after V1 and if particularly second segment limited is encountering a Microburst(ofcourse ypu should not takeoff within sight or radar coverage of any thunderstorm cell..but if a severe speed lag or speed burst occurs close to or at V1 im the given scenario with second segment climb limited case..it might be better to abort if on a dry runway Do expect an overrun and so exert maximum brake energy..and expect a fire in the wheel well or even overrun and crash at the end of an overrun.You have the choice to push throttles to max thrust(Firewall) and totate at a slightly higher speed to countermand the debilitating effects of the microburst during the first and second segment..not forgetting NOT to raise the gear or change any configuration except after flying through the shear..typically past 1500 feet.


text:
What is the flap extension schedule on approach for an airliner?
I understand that there are probably no set altitudes and speeds for flaps extensions, but can someone with insight provide a general guide for speeds, altitude and flaps for an ILS approach in good weather for a Boeing 777-300ER with a landing of Flaps 25 and $V_{ref}$ of 147 knots.
Something like this:
Alt: 5000 ft - Speed: 210 kts - Flaps 1
Alt: 4000 ft - Speed: 190 kts - Flaps 5...

On most Boeing twinjets (don't know about 747), the flap manoeuvre speeds can be derived or at least estimated with reasonably good precision by adding increments of 20 knots to VREF for the highest landing flap, e.g. to VREF30 for the 777. Minimum clean speed on these aircraft is typically around VREF30+80. The approach speed schedule recommends to extend each flap as you decelerate through manoeuvre speed (up to typically plus 20 knots). This means e.g. on a 777:
Deceleration through - select:
VREF+80 - F1
VREF+60 - F5
VREF+40 - F15 or 20 (15 can be skipped)
VREF+20 - Land flap (25 or 30)
Health warning: This is all from memory. If nobody else can chip in before Monday, I'll try to find quotable sources.
Best wishes,
M


text:
Is there something like a table of aircraft required runway lengths?
I'm looking for a chart showing the minimum length a runway can be for various aircraft to land and take off.
Does something like this exist?

You'll have to use the individual performance charts for the particular aircraft in question using the ambient atmospheric conditions for the particular day in question, usually computing both the ground roll length and obstacle clearance lengths for a particular takeoff technique.

It's aircraft specific as part of the operating limitations

Aircraft manufacturers issue the manual of aircraft characteristics of each type of aircraft. The reference documents provide airlines, MROs, airport planners and operators with the general dimensions of the aircraft, the necessary information for ramp, servicing operations or maintenance preparation. Minimum length for take-off and landing often include in it.
Here is the link for the documents for several major Airliner manufacturer:

Airbus
Boeing
Bombardier
Embraer


text:
Is turboshaft fuel efficiency affected by N2 loading?
When using a free power turbine turboshaft, does fuel burn get affected by N2 loading? I am asking as I want to in the future bench test a turboshaft for fuel burn, but I don't know if the loading would affect the fuel burn.

What is N2 in this case? Are you referring to engines with a two spool gas generator (three spools in total) or a single spool gas generator like the PT6 (two spools in total)?

PT6 style, 2 spool

Based on the comments, I think you are asking: does the fuel burn get affected by loading on the gas generator shaft?  And by loading, I think you mean the load through the accessory gearbox to drive things like oil pump, fuel pump, alternator, etc.  Yes, those absolutely affect the fuel burn.  Think about the consequences if they didn't. If you could pull 10x as much power out through the oil pump without affecting fuel burn, then you've created energy for free and violated the laws of thermodynamics.  So yes, that affects the fuel burn.  The question is, do it affect it much?  Not much, but probably enough that you'd need to account for it. The amount of power drawn by the accessory gearbox is relatively small compared to the amount drawn by the power turbine. I would guess it's a few percent.  But an error of a few percent in fuel burn calculations is probably not acceptable.  So you'll want to account for it.

Thanks for the reply. I think my question is confusing. I am talking about the power turbine, which in a engine with the compressor and high pressure turbine on one shaft, and the power turbine on its own, woundnt N2 be the power turbine?

Ok. There are different conventions. So you are asking does the loading on the power turbine affect fuel burn. Absolutely. It will make a huge difference.


text:
What is the relationship between fuel mixture and RPM in a reciprocating engine?
I'm doing a project on a safety occurrence but I don't understand how the RPM of an engine is affected by the fuel mixture.
How does a richer than normal mixture result in lower RPMs?

I assume you are referring to a fixed pitch propeller because a constant speed propeller will always hold the same speed as the governor automatically changes the blade angle.
Just like any piston motor there is an optimal mixture. Richer or leaner results in lower power. Planes are set up to run rich at full rich mixture so leaning during cruise or descent will produce more optimal power which will affect rpm slightly in a fixed pitch application. Excess fuel displaces oxygen which decreases power flighty.


text:
Carb Heat and Lycoming Engines
Why is Carb Heat less of an issue on Lycoming Engines? and if this is true, how much less of an issue is it?

It's because the spider duct that connects the carb to the intake runners going to the cylinders is cast into the oil sump and the carb mounts directly to that. So the carb gets a lot of engine heat that warms the carb body by conduction. Also, it's getting radiant heat from the sump directly above.
On Continentals the carb is insulated from the engine by its mounting and location relative to the sump.  Continentals without pressure cowls like J-3 Cubs are the worst for carb ice formation.
Carb icing is relatively rare on Lycomings but is still possible if the conditions are sufficiently favourable, so you still have to use normal carb heat protocols.

I get regular icing in Lycoming  o-320 equipped c172s while at low cruise and taxi power, but I am in a cool humid climate. not every flight but frequent

Yeah at say 65F and 90% humidity you will get it on Lycs.  My glider club's Pawnee with an Lyc O-540 appears to have had a carb ice incident lately.  My own O-290 has never shown signs of carb ice. Knock on wood.

I had a pair of Lyc O-320s (150hp) ice up during cruise in an Apache.  I've never had an icing problem in TCMs.  Just one more datapoint...

Not a big event in any case, engine gets a little rough or low on power, add heat for a minute then remove heat and increase throttle a bit to reduce recurrence. If I even suspect  due to weather I will carb heat for 10-20 seconds to see if it makes a change.

I think the question is incorrect - should be why is carb icing less of an issue on Pipers vs Cessnas when they are carburated.  And then it comes to carb placement. On Pipers, the carb is in a warmer place vs Cessnas and thus less susceptible to icing.


text:
Causes of High CHTs
I have a Long EZ with a Lycoming O-320 E2D. It had a complete top-end overhaul two years ago, in June 2017. All four cylinders were relined, and pistons and rings were replaced. Since then the aircraft has been hangered, in Oregon for one year, and then in Arizona (very dry). Since the top end overhaul the engine has had only 25 hours, and still has break-in oil in it. (one oil change six months ago).
The aircraft had thirty year old avionics, including a unreliable EGT/CHT gauge connected to only one cylinder. Recently I installed a new Dynon HDX Flat screen system with a full Engine Instrumentation (EMS) system that monitors and displays CHTs and EGTs on all four cylinders.
The problem is that now I can see the CHTs on all four cylinders, and they are much higher than I think they should be, even on the ground at idle. Lycoming documentation says absolute maximum CHT is 500F and maximum for continuous operation is 450F.
The first time I noticed it (two weeks ago), I had been taxiing or sitting waiting to take off for 20-30 minutes, and the CHTs on cylinders 3 & 4 were over 450F. (440F and 463F).
I took it to the local FBO and had them check it out. They did a compression check (all four cylinders were over 77/80), and bore-scoped the cylinders (all four were pristine, the A&P said that the cylinder walls appeared to not even be broken in yet). The only recommendation was that the engine baffling was in very poor shape.
So I completely rebuilt all the engine baffling. But this did not fix the problem. Even on the ground, taxiing out to the runway, CHTs on 3&4 climbed to over 400F, although they did not get to 450F. I did a Test flight, and in the climb-out (90-100kt, 2480rpm) CHTs would climb to 430F. Once I reached altitude and leveled off and accelerated to 130Kt, the CHTs settled back down to mid 300s. Another strange thing is that the cylinders that are reading high are inconsistent. On the ground, it is 3 & 4 that read higher. During climb-out in flight, cylinders 2 & 3 are the high ones. This sounds to me like an airflow issue, like the baffling is not right.
So this is my question, Given that compression checks are good, indicating valves are ok, and the cylinder walls are clean indicating no top end corrosion since the overhaul, what else can cause high CHTs? I have been told that engines run hotter than normal during break-in, but is this factor alone sufficient to explain these readings? What else should I be checking? I don't want to be relying on an engine that has a fundamental issue that might cause it to seize up on me.
Thanks in advance!

Are the temperature probes reliable? Are the electronics properly grounded where they should be? What are the oil temperatures doing?

Agree with @AEhere, you should check them against an infrared thermometer or some other method to confirm the temps are reliable. Also, are you leaning the engine on the ground?

One issue with rear engine airplanes is that there is not a lot of airflow into the engine on the ground. For front-mount aircraft, the prop pushes air through the cowl helping cool the engine. This is a pusher aircraft and the prop doesn't push air into the cowl on the Long EZ. It's been an issue for the Long EZ for a while. Also, have your A&P check the mag timing. Some people have reverted to deflector plates inside the cowling to deflect the air up towards the cylinders.

What's the issue? You say climb reaches 430F, that's below the 450F max continuous, and your cruise temps are in the mid 300s. That all sounds okay.

380° may be "in the green" but it's by no means OK.  How old is the baffling?  Also, if you are seeing high temps in AZ in the summer...well...that happens when the ambient cooling air is 105°F.  Still, look into the baffling.

Redid all baffling as it was old and not good. The Sensors are all new Sensors part of complete Dynon EMS system. Oil temp is ok, it varies between 160F and 175F. As to what the issue is, I do not know, I am told by other pilots that temps over 400 on the ground are an indication that something is wrong... I'm trying to determine whether there might be an issue that will come back to bite me.

This is an air cooled engine right?  Three things matter bigtime: baffling, airflow and ambient temp.  So you have a) deteriorated baffling, b) testing at 0 mph on the ground outside of the normal flight airflow, and c) Arizona in June. Also break-in.  It reminds me of the way in accident reports, a bunch of little things stack against the pilot.  So it is with this engine, it is really adverse conditions for it.

It was baffling!  Completely redid the baffling and the CHTs came down by 50-70 degrees

Thanks for coming back to update this!

Your temperatures don't sound all that bad for breaking in cylinders, but you should go back over the baffling.  The baffling is there to maintain pressure in the plenum with the help of those rubber strip seals, and to force air at high velocity between the cylinder fins as it makes its way through to the low pressure side.  The baffling has to be right against the fins so air can't go around the fins.  Baffles that don't fit properly prevents the air from picking up enough heat from the fins and even if you have normal temps you can have hot spots.
Yes cylinders will run hot as the piston rings wear off the ridges of the honed surface of the cylinder wall.  On the other hand, I wouldn't be surprised at all to see high cylinder temps after 20 minutes of ground running on any tightly cowled pusher where the airflow is only from a gentle suction on the exhaust side from the prop.  If you're at idle and the wind is behind you opposing what little cooling flow there is, typical when sitting in a line up on a taxi way, the engine is getting very little cooling flow at all so naturally you have an Easy Bake Oven running behind you.
In a Long Eze you should avoid long idle periods like that, especially during break-in.  Especially out of wind.  And in fact, until break-in is complete (oil consumption will stabilize and CHTs will drop) you should avoid flying in circumstances where you have to sit in line on a taxiway without shutting down (At Oshkosh I remember watching the Eze drivers shut down, get out and push their planes along as the departure line of aircraft moved along to avoid the 20 minute ground run cooking their engines during the post airshow escape crush).
Another minor point is, if the CHTs are working off thermocouple washers instead of the screw-in probes of the threaded hole provided for the purpose under the Lycoming cylinder, the CHTs will read higher because the area around the plug where the washer senses gets the heat from the plug, which is always hotter than the surrounding aluminum. Especially if they are washers on the lower plugs (Continentals use the washers, usually on the top plugs - Lycomings have the dedicated temperature probe well underneath, but sometimes you will find the washers used on Lycs if it was a later add on).

Note.  I did a rewrite because I overlooked the statement that Charles had rebuilt his baffling already.  The original version assumed that hadn't been done.

Yeah I've always been taught to break in engines under gentle conditions, so in AZ, yikes. Maybe be at the airport at 5am when it's cool, and go as quick as practicable from startup to takeoff. Climb enough to get the engine some cool air, and just orbit to do the break-in hours.

Yes, thanks for the Oshkosh stories... I feel better about this now... and it was baffling!  Completely redid the baffling and the CHTs came down by 50-70 degrees. and Yes, I am at Prescott (5000 MSL) so not quite as hot, but I was flying down to Phoenix (Scottsdale) a lot and was seeing temps that concerned me.... Better Baffling has taken those way down now.

And my EGTs are working off thermocouples in the exhaust stacks, but I think you meant the CHT sensors, and these are indeed working off thermocouples in the Lycoming pre-installed sensor ports on the heads.

Yes, CHT (slapping forehead)...  My plane has an O-290 and I got a gauge and a bayonet thermocouple, then discovered the gauge I had was only calibrated to work with washers, which it came with, so I just installed that and put it on the top left cyl.  A gauge to work with the bayonet was too expensive.